So far, a huge breakthrough in the world of electronics has been the discovery of the electrical properties of semiconductor materials. These are mostly crystalline materials, the conductivity of which (electrical conductivity) can be changed in a wide range by introducing impurities, changing the temperature or changing the intensity of light falling on the semiconductor.

Photoresistors – these are electronic components that use the photoelectric properties of semiconductors. In this category you will find various types of photoresistors. These are devices that will surely be useful to you in various projects. They can be used both to build automatic machines and advanced robots. We invite you to familiarize yourself with all the products that you will find below!

Photoresistors and basic laws of physics

In order to understand how photoresistors work, it is worth recalling some basic physics issues. One of the most elementary laws of a physicist is Ohm's law, which is known to every hobbyist or professional dealing with electronics and electricity. Ohm's law states that the value of the current flowing in a circuit depends on the voltage and its resistance. The electronic element that will allow us to apply this law in practice is the resistor. The main parameter is resistance. At a time when semiconductors are in the lead in electronics, thanks to their properties, a modified version of the resistor was created. This latest version is the photoresistor you can buy in this category!

Photoresistors are semiconductor elements made of semiconductor layers applied on an insulating substrate. The construction of the photoresistor is multi-plane. The photosensitive material is separated by two electrodes connected to the leads. The photosensitive surface is covered with a transparent window. Under the influence of changes in light intensity, photoresistors change their resistance, regardless of the direction of the applied voltage. Increasing the illuminance reduces the resistance, and therefore increases the intensity of the current flowing at a constant voltage. Photoresistors are characterized by a linear family of current-voltage characteristics. This property is a great advantage in the case of electrical circuits.

Photoresistors – whether it is worth to use them?

Due to the very high sensitivity and simplicity of the measuring system, photoresistors are very often used to measure temperature by measuring the intensity of radiation. This method of measurement has many advantages. Photoresistors are perfect wherever it is necessary to identify the intensity of radiation - in heat detection systems, in advanced fire protection systems. This, of course, is not all. When it comes to the use of photoreistors, you can also safely apply them to systems whose operation depends on the time of day (automatic closing and opening of roller shutters in your home, automatic lighting control, heating system).

In the Botland store, in addition to classic 100 mW photoresistors and bright resistances in the ranges of 5-10 kΩ, 10-20 kΩ, 20-30 kΩ, 50-100 kΩ, you will also find photoresistors compatible with Arduino electronic modules. These modules have an analog output that you can use to directly connect the photoresistor to your development kit. This is a very simple way to create your projects and discover many new functions and possibilities of photoresistors!

Photoresistors – the most important parameters

To choose the right product for your project, see the most important photoresistors parameters. Detailed specification of a given resistor can be found in its product card.

The basic parameters characterizing photoresistors include:

  • spectral sensitivity - is the dependence of the electrical resistance on the illuminance,
  • dark resistance "RD" - photoresistor resistance in conditions without lighting,
  • resistance "Rxx" ('xx' means the illuminance in lux (lx)) - it is the resistance of the photoresistor at a given illuminance value. Manufacturers in their catalog cards include information about resistance (eg R10, R50). It is also called light resistance.
  • coefficient "n" - the ratio of the dark resistance to the resistance for a given lighting value, e.g. n = RD / R50,
  • maximum operating voltage,
  • maximum power,
  • switching time
  • working temperature.

Enjoy your shopping! If you have any questions, feel free to contact us - feel free to write and we will try to help!